Heart As A Combustion Engine

( Originally Published 1921 )

In many ways the heart resembles an internal combustion engine, such as is used in automobiles. The analogy between the heart and such an engine is helpful in getting the true appreciation of what the heart really is, and leads to wise management.

So many people have been compelled to learn about gasoline engines during the war period, that it is hardly necessary to explain that the internal combustion engine is made to go by the explosion of gasoline in the cylinders, while a steam engine is made to go by passing steam into the cylinders and the steam pushes the piston back and forth. The heart muscle corresponds to the cylinder of the gasoline engine, and gets its energy from the combustion of food products.

When a gasoline engine has had a single explosion in the cylinders, nothing more can happen until sufficient time has elapsed for more gasoline to be taken in. In the meantime, there
being no gasoline present, nothing happens. In the same way a stroke of the heart is followed
by a period during which, no matter how much it is stimulated, it will not work. In other words,with each stroke of the heart, all its available energy is used up, and more must be produced before it can beat again. The beating of the heart; therefore, consists of a succession of ex-plosions of energy, just as each throb of the automobile engine represents an explosion of gasoline in its cylinders.

To get good results from an engine, we need pure gasoline, a proper mixture of air, regular ignition, and a constant load. If you throw out your clutch suddenly when your engine is speeding up, it races ; if you overload it, it pounds. The same thing is true with your heart. To get the best results we must have a proper supply of the right kind of food products, neither too much nor too little. We must have also the kinds that burn up and leave no residue.

The impulse generator of the heart lies normally in the auricle, and acts much like the commutator of the engine, which should send an average of seventy impulses a minute, and these
impulses should spread quickly over the heart, causing it to contract and do its work.

The blood pressure, like the load on the en gine, must not be too low, because that makes the heart palpitate, or race, and it must not be too high, because that makes the heart labor or knock.

If you want to find out whether a particular food is good to produce energy in the heart, burn it up and see how much heat you can get out of it. If it produces little heat and a bad smell, it is not good food to make the heart do its work well, just as heavy crude oil is not good to use in an automobile.